What are stereograms?In a nutshell, stereograms are a way to see images with a three-dimensional perception.
The stereograms doesn't need any special devices (ie. red-green glasses or particular projectors) it's enought to look to the image with a particular technique.
How can we see the world in 3D?When we watch an object, we have the natural sensation that it has a third dimension, i.e.: we have the perception that different points of it are at a different distance from ourselves.
This perception accrues from a combination of different factor:
- light and shadow effects
- stereoscopic view
When we watch an object, our right eye see something different from left one. To try this effect put your hand in front of you, then close your left eye, now what you see is the image from your right eye only, now istantly close your right eye and open the left one, now you see the image from your left eye only. Can you see the differences? The big one is usually the position of your hand respect to the background, but if you pay attention you'll notice also some differences in the hand itself (these differences can be great ones or small ones depending by the position and orientation of your hand).
When we watch around two different images deriving from the two eyes are given to our brain that elaborate them and estimate the distances of the points in the image. So we have the 3D perception.
View 3D photos and moviesIt's not hard to see a photo in 3D. There are some devices that permits so. They are composed by a photo camera with 2 separated lens, when you make a click, it makes two photos, one for each lens.
You can develop the photos and watch them normally, but it is possible to use an ottic device that with a simple principle force your right eye to see one photo and the left one to see the other.
This way the brain has got the illusion to see a 3D image.
The same effect can be obtained for a movie, but if it is simple to films a scene with a double camera. There is the necessity of two little monitors to project the films separatly over the two eyes. And many people can turn up their nose to use that kind of "strange objects" to see a film.
Red-Green glasses. A simpler solution to see films in 3D came from the use of the famous red-green glasses. This glasses have got one red lens and a green one.
WORK IN PROGRESS!!
Here is a List of same stereograms realized by me.
This is a list of links, in every page you will find a stereogram and, under it, the solution.